Summary
• Norbord’s biomass plant opened in February this year.
• It generates 5MW of heat for thermal oil, plus 5MW for steam generation.
• The plant consumes bark and wood residue.
• Before the plant opened, Norbord had already reduced fossil fuel consumption by 45%.

Since its official opening in February this year, the economics of the biomass plant at Norbord’s chipboard and MDF production facility at Cowie in Central Scotland have become even more favourable. At that time, it was said that the £2.5m investment would justify itself inside 28 months but the subsequent huge increases in energy costs have significantly reduced this payback period, according to Steve Roebuck, the company’s director of health, safety and environmental affairs.

In generating 5MW to heat the thermal oil pumped through the press to cure the MDF, it was initially estimated that the biomass plant would save Norbord £12,000 a week in gas costs – but the price of gas has risen by around a third since then, Mr Roebuck said. A further 5MW is available for steam generation for the plant boiler where the wood chips are ‘cooked’ prior to refining for panel production. Net rated thermal input is 14MW to give an efficiency of 70%.

Fuel trials

The project has involved environmental impact assessments and tests to show that the plant is the best practical environmental option. Fuel trials, now nearing completion, have shown the plant performing twice as well as anticipated by a theoretical air quality model. The plant, now at full capacity, also meets UK and EU targets for fossil fuel combustion, according to Mr Roebuck.

The biomass plant consumes bark and wood residue from the manufacturing process, with none from outside sources. Mr Roebuck confirmed that input is process residues that have reached the end of their useful lives; no virgin wood is used for energy because “it is far too valuable to burn”. In the past, around 24,000 tonnes of the Cowie facility’s annual post-recycling residues had been ending up in landfill – “and that’s what this plant is all about”, he said.

Even before opening the biomass facility Norbord had achieved a 45% reduction in fossil fuel combustion over the previous five years via energy efficiency measures and capital investment in renewables.

While noting that the government encourages the burning of biomass through the issue of Renewable Obligation Certificates, Mr Roebuck pointed out that no differentiation has been made between the different biomass grades. “Power companies receive the same for burning ‘virgin’ or clean recycled material, which could be used for manufacturing, as for waste material which has no other value but as fuel,” he said.

Mr Roebuck contends that waste should go to landfill “only after all recyclable parts have been recovered and the rest burned to produce energy”. He believes that, at a time when demand for wood byproducts is beginning to exceed supply, a large volume of potential feed material is being neglected. He points to a Defra document published last April which estimates that between 5-10 million tonnes of contaminated wood and biomass is going into landfill each year. “This is the only untapped source we have for energy generation but it does require government intervention to mobilise that wood,” he argues.

Mapping wood flows

Mr Roebuck is calling for the compilation of nationwide statistics covering available wood from forests as well as for the mapping of wood flows. And just as importantly, he said, there is a need to identify and constantly monitor waste wood going to landfill. Incentives are required, he added, to secure the uneconomic wood available in the forest and to ensure the plants are built to guarantee an end use for this material.

Norbord has welcomed the fact that the government is considering the introduction of “banding” to separate different types of biomass fuel. For his part, Mr Roebuck believes that any such system should be based on the type of fuel rather than on the technology, and should be geared towards ensuring that the material in surplus – namely, contaminated wood – is tapped into.

At the official opening of the biomass plant at Cowie, minister of state for energy Malcolm Wicks described it as “a good example of what biomass should look like in the future”. And with many months of operational experience now under its belt, Norbord is also confident that it has adopted the most appropriate model. The plants that make up Norbord Europe currently derive an average of 75% of their energy requirements from the “left-overs” from board-making and recycling processes. While no definitive decision has yet been taken, the potential for introducing further biomass capacity within its European operations is “under review”, said Mr Roebuck. “We think it is the right thing to be doing.”